1. Reports of tables regarding research on group housing of sows; Research on (the change to) group housing of sows amongst pig farmers who keep 100 breeding sows or more. AgriDirect B.V., Roggel (In Dutch);AgriDirect,2008
2. From intentions to actions: A Theory of Planned Behavior;Ajzen,1985
3. Attitudes, personality and behaviour;Ajzen,1988
4. The Theory of Planned Behavior;Ajzen;Organizational Behavior and Human Decision Processes,1991
5. The influence of attitudes on behaviour;Ajzen,2005